The United Nations has begun a polio vaccination campaign in Gaza

UN agencies and the Palestinian Health Authority began the first round of polio vaccinations for 640,000 children in Gaza on Sunday (1 September). The Israeli military and Hamas are holding a three-day ceasefire in the central, southern and northern Gaza Strip starting Sunday, but the World Health Organization says it may have to be extended to four days.

Juliette Touma, director of communications for the United Nations Relief and Works Agency for Palestine Refugees in the Near East, said: "Today is a test of whether all parties to the conflict respect the pause in these areas so that Agency teams and other health workers can deliver the first round of polio vaccine to children."

Who officials say at least 90 percent of children need two doses of the vaccine, with a second dose four weeks later, but much of the Gaza Strip has been devastated by fighting, making it a huge challenge.

"Children continue to be exposed to the virus without borders, checkpoints or battle lines," Touma said. Every child in Gaza and Israel must be vaccinated to curb the risk of the spread of this vicious disease."

On the war front, Israeli forces continued to battle Hamas militants in several areas of the Palestinian enclave. Residents said Israeli troops blew up several houses in Rafah, near the Egyptian border, while tanks continued fighting in the northern Gaza City suburb of Zeitoun.

The Israeli military said it recovered the bodies of six hostages Sunday from a tunnel in southern Gaza, apparently killed shortly before Israeli troops arrived.

Israeli Prime Minister Benjamin Netanyahu said Sunday that "Israel will not stop... Until the killers of the six hostages are caught... The people who killed the hostages did not want a deal."